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Wrought processing of brittle target alloy for sputtering applications

a target alloy and sputtering technology, applied in vacuum evaporation coatings, ion implantation coatings, sm, etc., can solve the problems of coarse and non-uniform ta precipitate-phase microstructural morphology of target a, and difficulty or impossible to conventionally roll-process

Inactive Publication Date: 2002-01-10
HERAEUS INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0010] A further object of the present invention is to enable the formation of a sputtering target which is constituted in such a manner as to cause the magnetic layers which are sputter deposited onto the surface of a data / storage disk, to exhibit improved physical / magnetic characteristics.

Problems solved by technology

However, multi-component Co alloys with primary elemental additions such-as Cr, Pt, Ni (0 to 30 atomic %) and secondary elemental additions such as Ta, B, Nb, Sm, Fe, Si, Zr, W, Mo, V, Hf, and Ti (0 to 30 atomic %) can be very difficult or impossible to conventionally roll-process if the concentration of limited solid-solubility elements is excessive.
However, as-cast targets have several unfavorable microstructural characteristics such as large grain-size, gross segregation of matrix and precipitate phases, through thickness microstructural and chemical gradients and porosity.
Target A was fabricated using standard techniques and possessed a coarse and non-uniform Ta precipitate-phase microstructural morphology.
These results demonstrate that if target precipitate and grain uniformity are not controlled, the resulting Coercivity response of the sputtered film can be diminished and the disk-to-disk Coercivity consistency can be adversely effected.
This lead to ingots with a high elemental concentration fracturing during hot-rolling.
Unfortunately, until now, the use of as-cast targets has been the only process option for several brittle Co-base alloys used in the data-storage industry.
The presence of severe target erosion profiles also promotes a point source sputtering phenomena which can result in less than optimum deposited film thickness uniformity.

Method used

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  • Wrought processing of brittle target alloy for sputtering applications
  • Wrought processing of brittle target alloy for sputtering applications
  • Wrought processing of brittle target alloy for sputtering applications

Examples

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example 2

[0056] An alloy containing Co-15Cr-4Pt-5Ta-2B was heated via induction under a vacuum of between 10 to 40 milliTorr until molten and cast to form an ingot with a thickness-to-width aspect ratio between 0.1 to 0.3. The temperature of the ingot was allowed to reduce in a controlled fashion for a period of 1 hours until a temperature of 1000.degree. F. was reached. The ingot was subsequently annealed between 2000 F. to 2500 F. for 10 hours and hot-rolled between 1200 F. and 2100 F. for a total reduction of 50% and allowed to cool in a controlled fashion from the rolling temperature to 300.degree. F. in 6 hours.

[0057] FIG. 7 is a Scanning Electron Microscope (SEM) micrograph using Back Scattered Electron Imaging (BEI) depicting the microstructure of the ingot and resultant as-cast targets manufactured using conventional paradigms. EDS (FIG. 8) and Auger analysis confirm that the matrix phase (gray appearing phase) is composed of Co, Cr, Pt and Ta, that the first precipitate phase (light...

example 3

[0060] Two alloys, Co-18Cr-6Pt-9B and Co-12Cr-8Ta were heated via induction under a vacuum of between 10 to 40 milliTorr until molten and cast to form ingots with thickness-to-width aspect ratios of 0.4, 0.25 and 0.07, respectively. The temperature of the ingots were allowed to reduce in a controlled fashion for a period of 1.5 hours until a temperature of 1000.degree. F. was reached. All the ingots was subsequently annealed between 2000 F. to 2500 F. for between 6 to 15 hours and hot-rolled between 1800 F. and 2500 F. for a total reduction of 50% and allowed to cool in a controlled fashion from the rolling temperature to 200 F. in 2 hours.

[0061] FIG. 11 illustrates Scanning Electron Microscope (SEM) micrographs using Back Scattered Electron Imaging (BEI) depicting the microstructure of the ingots and resultant as-cast targets manufactured using conventional paradigms. SEM-EDS and Auger analysis confirm the following phase compositions for the different alloys:

[0062] Co-18Cr-6Pt-9B:...

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Abstract

An ingot of material which is normally too brittle to allow successful rolling and wrought processing is formed so as to have a thickness-to-width ratio of less than about 0.5 and is annealed in a temperature range of 1000° F. to 2500° F. for a preselected time. The ingot is then rolled in a temperature range of 1500° F. to 2500° F. Additional / optional annealing of the resulting rolled plate in a temperature range of 500° F. to 2000° F., or between room temperature and 1500° F., and / or a final annealing between 500° F. and 1500° F., is possible. Sputtering targets are cut out of the rolled plate and used for the manufacture of storage disks.

Description

[0001] This invention relates generally to multi-component cobalt alloy material which is used for sputter deposition of a magnetic layer on a data / storage disk, and more specifically to a method of producing an alloy material, such as that based on a brittle Co-based alloy, which exhibits microstructural and magnetic properties that are optimized for magnetron sputtering, and which finds application in the formation of a sputtering target.DESCRIPTION OF THE RELATED ART[0002] The manufacture of storage disks and read / write heads involves the use of target materials that are used to sputter deposit a thin film media onto a suitable substrate. Cobalt-based alloy targets are frequently used for this purpose.[0003] However, multi-component Co alloys with primary elemental additions such-as Cr, Pt, Ni (0 to 30 atomic %) and secondary elemental additions such as Ta, B, Nb, Sm, Fe, Si, Zr, W, Mo, V, Hf, and Ti (0 to 30 atomic %) can be very difficult or impossible to conventionally roll-pr...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): C22F1/10C23C14/34
CPCC22F1/10C23C14/3414
Inventor BARTHOLOMEUSZ, MICHAELTSAI, MICHAELDEODUTT, ANAND
Owner HERAEUS INC